Application drums, or lay-down drums as they are often called, are known in the prior art. The drums are used in production of absorbent products such as nappies, incontinence articles and the like. The drums are provided with material engagement means which receive a piece of material from a supply means and then apply it to an underlying sheet of an absorbent product positioned on a moving conveyor belt. The receiving location and the delivery location are typically 180.degree. opposed and the drum rotates continuously so as to pass through the receiving location and then the delivery location.
The piece of material may be of any type, but is typically a pre-formed piece, such as an absorbent core or other absorbent layer. The engagement means is generally arranged so that an under-pressure (e.g. a vacuum)is applied to the material engagement means on the drum when the article is in the collecting position. The under-pressure is applied through perforations in the engagement means.
The under-pressure is maintained on the material engagement means as the drum rotates, until the drum has rotated so that the material piece attached thereto is in contact with the conveyor belt, or the part-formed absorbent article thereon. An over-pressure is then applied to the engagement means so as to secure release of the material piece from the application drum.
In lateral production techniques, the absorbent articles being formed are typically placed head-to-toe across the conveyor belt (i.e. one article is rotated 180.degree. with respect to the next). If, as is normal, a material piece must be laid onto the part-formed articles at a location which is not in line with, or to one side of, the centreline of the drum, then two laterally-spaced application drums (or a similar arrangement) are often used. In such a case, each of the drums delivers a material piece to alternate ones of the part-formed products.
The use of two independent drums is of course more expensive, may require complicated synchronisation between the drums and the material supply equipment and normally involves more auxiliary equipment (such as pumps and pressure lines for example). A great deal of space may also be required, especially where the drums must be longitudinally offset with respect to each other as well as being transversely offset. Further disadvantages will be apparent to the man skilled in the art. To summarise, the use of two application drums is thus clearly undesirable.